1. Technical Field
The present invention relates to a bipolar high frequency treatment device, which aims at improvement of insulation properties between a first forceps blade and a second forceps blade.
2. Background Art
As a conventional forceps type electric treatment device, for example, there is a device disclosed in Japanese Patent Application Laid-Open No. 11-155875 (Patent Document 1). This forceps type electric treatment device of Patent Document 1, according to the claims for the patent, is “a forceps type electric treatment device, comprising: a flexible catheter tube insertable into a body; a first forceps blade installed at the distal end side of the catheter tube and having a first cup-shaped concavity formed therein; a second forceps blade installed at the distal end side of the catheter tube and having a second cup-shaped concavity formed therein; a support device holding the first forceps blade and the second forceps blade so that they are able to move around a fulcrum shaft to open and close and that the first concavity and the second concavity come face to face; a first electrode formed in the first forceps blade; a second electrode formed in the second forceps blade; and voltage supply means connected to the proximal end side of the catheter tube so that high frequency voltage is supplied between the first electrode and the second electrode, wherein an intermediate insulating spacer is interposed between the first forceps blade and the second forceps blade that are held so that they are able to move around the fulcrum shaft to open and close” (see claim 1 of Patent Document 1). In a preferable mode for carrying out the invention, the device is a forceps type electric treatment device “wherein an insulating member is interposed between the fulcrum shaft and the first forceps blade and/or the second forceps blade” (see claim 2 of the Patent Document 1). In another preferable mode the device is a forceps type electric treatment device “wherein a sideward insulating spacer is interposed between the first forceps blade and/or the second forceps blade, which are held so that they are able to open and close around the fulcrum shaft, and the support device” (see claim 3 of Patent Document 1). In still another preferable mode the device is a forceps type electric treatment device “wherein a portion of the sideward insulating spacer protrudes from the outer periphery of the support device” (see claim 4 of Patent Document 1). In a further preferable mode, the device is a forceps type electric treatment device “wherein the sideward spacer has an elongated shape along the longitudinal direction of the support device” (see claim 5 of Patent Document 1).
Although there is no limitation imposed on the shape of the “intermediate spacer” in the claims of Patent Document 1, it is clear that the intermediate spacer is a disc-shaped flat plate in view of the whole specification.
Consequently, when the first forceps blade and the second forceps blade are in a closed state, the space between a first link rear end portion and a second link rear end portion, and the space between a first link and a second link become an insulating distance. The forceps type electric treatment device to be inserted into the body is has an insulating distance of approximately 0.5 mm since the diameter of the catheter tube insertable into the body is 2 to 3 mm. The high frequency current has a property of running through the surface of a conductive body. Consequently, if the insulating distance is approximately 0.5 mm, it is not sufficient for the purpose of insulating, and there is a possibility of causing the short-circuit or a leakage of the high frequency current.
Furthermore, in the forceps type electric treatment device of Patent Document 1, as shown in FIGS. 1 and 3 of Patent Document 1, since a pair of support elements in a bifurcated shape are formed at the top end portion of the support device, a pair of support elements are sometimes extremely opened or have torsion when the top end portion of the support device is processed. Then, in case the first forceps blade and the second forceps blade are attached to the top end portions of the pair of support elements, the attachment causes shaking or the first forceps blade and the second forceps blade are incapacitated to pivot smoothly because they are fastened too tight.
In the forceps type electric treatment device of Patent Document 1, as shown in FIG. 3 thereof, one conducting path is formed by the first forceps blade, the first link rear end portion, the first link element, a driving element and a conductive wire, and further, the other conducting path is formed by the second forceps blade, the second link rear end portion, a metallic washer, the support element, the support device and a coil tube. In the forceps type electric treatment device having a configuration according to Patent Document 1, when the first forceps blade and the second forceps blade are in an opened state, there is a possibility that the first forceps blade and the second link rear end portion are electrically contacted, and further, the second forceps blade and the first link rear end portion are electrically contacted. Consequently, for fear of such electrical contact, there arises an inconvenience that the first forceps blade and the second forceps blade cannot be opened to the fullest, and the first forceps blade and the second forceps blade cannot be widened so as to fit to the size of the lesion region existing in the body. Consequently, it has been practically impossible to open the first forceps blade and the second forceps blade so as not to contact each other inside the body.    [Patent Document 1] Japanese Patent Application Laid-Open No. 11-155875
The present invention has been made in order to solve the above-described problem, and an objective of the present invention is to provide a bipolar high frequency treatment device, which does not cause a leakage or short-circuit of the high frequency current and is safely operable when the first forceps blade and the second forceps blade are electrified.
Another objective of the present invention is to provide a bipolar high frequency treatment device, which does not generate a leakage or short-circuit of the high frequency current, can realize a smooth opening and closing of the first forceps blade and the second forceps blade, and can easily control the maximum opening state with the first forceps blade and the second forceps blade.
Still another objective of the present invention is to provide a bipolar high frequency treatment device, which, even when the high frequency current is allowed to flow while gripping the lesion region with the first forceps blade and the second forceps blade, the lesion region tissue can be prevented from adhering to the first forceps blade and/or the second forceps blade.